Auto-crosslinking, cathodically depositable binders

Abstract

Auto-crosslinking, cathodically depositable binders which are water-dilutable upon neutralization comprising the reaction product of: (A) 2 moles of a polyepoxy compound with from 2 to 10 epoxy groups per molecule and an epoxy equivalent of from 100 to 1000; (B) 0.1 to 2.0 moles of a diamine, the nitrogen atoms being secondary-secondary or primary-tertiary; (C) from 1 to 10 moles of an alpha,beta-unsaturated monocarboxylic acid; and (D) from 0.5 to 10 moles of dialkanol amine and/or of a monoalkanol monoalkyl amine, whereby the weight ratios of the components are chosen in order that the sum of the epoxy-reactive hydrogen atoms of components (B) through (D) substantially correspond to the number of epoxy groups of component (A), and the binder contains from 0.5 to 2.5 basic nitrogen atoms and from 0.5 to 2.5 polymerizable double bonds per 1000 molecular weight units. The binders upon heating do not decompose and when employed in coating compositions provide good electrochemical characteristics and good surface qualities.

It is claimed: 
     
       1. Auto-crosslinking, cathodically depositable binders comprising the reaction product of: (A) 2 moles of a polyepoxy compound with from 2 to 10 epoxy groups per molecule and an epoxy equivalent of from 100 to 1000;   (B) 0.1 to 2.0 moles of an aliphatic and/or cycloaliphatic and/or aromatic diamine, the nitrogen atoms of which are secondary-secondary or primary-tertiary;   (C) from 0 to 10 moles of an alpha,beta-unsaturated monocarboxylic acid, and   (D) from 0.5 to 10 moles of a secondary amine, the weight ratios of said components being chosen whereby the said binders have an amine value sufficient to render said binders water dilutable upon neutralization with an inorganic or organic acid, and said binders being thermally self-crosslinking.   
     
     
       2. The binders of claim 1 wherein the polyepoxy compound of (A) is an epoxidized novolak resin. 
     
     
       3. The binders of claim 1 wherein the polyepoxy compound of component (A) has from about 2.5 to 5 epoxy groups per molecule. 
     
     
       4. The binders of claim 1 wherein the diamine of component (B) is present at from about 0.2 to 1.0 moles. 
     
     
       5. The binders of claim 1 wherein the monocarboxylic acid of component (C) is present at from about 2 to 5 moles, and said component (C) includes minor quantities of a saturated or unsaturated monocarboxylic acid having from 2 to 18 carbon atoms. 
     
     
       6. The binders of claim 1 wherein the secondary amine of component (D) is present at from about 1 to 5 moles of the dialkanol amine and/or monoalkanol monoalkyl amine, and the said component (D) includes minor amounts of dialkyl amines. 
     
     
       7. A water-dilutable, neutralized, auto-crosslinking, cathodically depositable paint binder comprising the reaction product of: (A) 2 moles of a polyepoxy compound with from 2 to 10 epoxy groups per molecule and an epoxy equivalent of from 100 to 1000;   (B) 0.1 to 2.0 moles of an aliphatic and/or cycloaliphatic and/or aromatic diamine, the nitrogen atoms of which are secondary-secondary and primary-tertiary;   (C) from 0 to 10 moles of an alpha,beta-unsaturated monocarboxylic acid, and   (D) from 0.5 to 10 moles of a secondary amine, the weight ratios of said components being chosen whereby the said binders have an amine value sufficient to render said binders water dilutable upon neutralization with an inorganic or organic acid, and said binders being thermally self-crosslinking.     
     
     
       8. The neutralized binder of claim 7 wherein the polyepoxy compound of (A) is an epoxidized novolak resin. 
     
     
       9. The neutralized binder of claim 7 wherein the polyepoxy compound of component (A) has from about 2.5 to 5 epoxy groups per molecule. 
     
     
       10. The neutralized binder of claim 7 wherein the diamine of component (B) is present at from about 0.2 to 1.0 moles. 
     
     
       11. The neutralized binder of claim 7 wherein the monocarboxylic acid of component (C) is present at from about 2 to 5 moles, and said component (C) includes minor quantities of a saturated or unsaturated monocarboxylic acid having from 2 to 18 carbon atoms. 
     
     
       12. The neutralized binder of claim 7 wherein the secondary amine of component (D) is present at from about 1 to 5 moles of the dialkanol amine and/or monoalkanol monoalkyl amine, and the said component (D) includes minor amounts of dialkyl amines. 
     
     
       13. Process for the production of auto-crosslinking, cathodically depositable binders, characterized in that: (A) 2 moles of a polyepoxy compound with from 2 to 10 epoxy groups per molecule and an epoxy equivalent of from 100 to 1000 are reacted with   (B) 0.1 to 2.0 moles of an aliphatic and/or cycloaliphatic and/or aromatic diamine, the nitrogen atoms of which are secondary-secondary or primary-tertiary ones, and   (C) from 0 to 10 moles of an alpha,beta-unsaturated monocarboxylic acid, and   (D) from 0.5 to 10 moles of a secondary amine, and   (E) the product of (A)-(D) is rendered water-dilutable through partial or total neutralization with inorganic and/or organic acids, the weight ratios of said components being chosen whereby the said binders have an amine value sufficient to render said binders water dilutable upon neutralization with an inorganic or organic acid, and said binders being thermally self-crosslinking.     
     
     
       14. Process according to claim 13, characterized in that the polyepoxy compound is an epoxidized novolak resin. 
     
     
       15. The process of claim 13 wherein the polyepoxy compound has from about 2.5 to 5 epoxy groups per molecule. 
     
     
       16. The process of claim 13 wherein the diamine of component (B) is present at from 0.2 to 1.0 moles. 
     
     
       17. The process of claim 13 wherein the monocarboxylic acid of component (C) is present at from about 2 to 5 moles, and said component (C) includes minor quantities of a saturated or unsaturated monocarboxylic acid having from 2 to 18 carbon atoms. 
     
     
       18. The process of claim 13 wherein the secondary amine of component (D) is present at from about 1 to 5 moles of the dialkanol amine and/or monoalkanol monoalkyl amine, and the said component (D) includes minor amounts of dialkyl amines. 
     
     
       19. The process of claim 13 wherein said process is carried out in the presence of an inert solvent. 
     
     
       20. The process of claim 19 wherein component (A) is simultaneously reacted with components (B)-(D) at a temperature of from about 50° to 150° C. 
     
     
       21. The process of claim 20 wherein said temperature is between about 100° and 120° C. 
     
     
       22. The binders of claim 1 wherein said ratios of said components are chosen whereby the sum of epoxy-reactive hydrogen atoms of components (B) to (D) substantially correspond to the number of epoxy groups of component (A), and whereby the said product contains from 0.5 to 2.5 basic nitrogen atoms and from 0.5 to 2.5 polymerizable double bonds per 1000 molecular weight units. 
     
     
       23. The binders of claim 1 wherein said component (A) is a diepoxide, said component (B) is present in an amount of 1 mole, said component (C) is present in an amount of 0 to 1 moles, and said component (D) is present in an amount of from 1 to 2 moles. 
     
     
       24. The neutralized binder of claim 7 wherein said ratios of said components are chosen whereby the sum of epoxy-reactive hydrogen atoms of components (B) to (D) substantially correspond to the number of epoxy groups of component (A), and whereby the said product contains from 0.5 to 2.5 basic nitrogen atoms and from 0.5 to 2.5 polymerizable double bonds per 1000 molecular weight units. 
     
     
       25. The neutralized binder of claim 7 wherein said component (A) is a diepoxide, said component (B) is present in an amount of 1 mole, said component (C) is present in an amount of 0 to 1 moles, and said component (D) is present in an amount of from 1 to 2 moles. 
     
     
       26. The process of claim 13 wherein said ratios of said components are chosen whereby the sum of epoxy-reactive hydrogen atoms of components (B) to (D) substantially correspond to the number of epoxy groups of component (A), and whereby the said product contains from 0.5 to 2.5 basic nitrogen atoms and from 0.5 to 2.5 polymerizable double bonds per 1000 molecular weight units. 
     
     
       27. The process of claim 13 wherein said component (A) is a diepoxide, said component (B) is present in an amount of 1 mole, said component (C) is present in an amount of 0 to 1 moles, and said component (D) is present in an amount of from 1 to 2 moles.